Five different cyclic nucleotide-independent protein kinases have been identified in rabbit reticulocytes and shown to phosphorylate various translational components including initiation factors and ribosomes. Three of the protein kinases have been obtained in highly purified form and the physical-chemical characterization and mode of regulation of these enzymes are being studied. They include casein kinase I and II and the hemin controlled repressor. Two other protein kinases, protease activated kinase I and II have been partially purified; further purification and characterization of the enzymes are underway.